I'm a gay man with many straight male friends. I've always had a straight friend I've considered one of two or three best friends. My friendships with them are, in many ways, more openly loving than the friendships with my gay friends. I've got a few ideas as to why. I've had no sexual feelings for them at any point in time, even though a few of them are incredibly good-looking.
Still, they seem to be much more comfortable being affectionate, even physically affectionate, with me and are much more willing to tell me they love me than they are with their hetero friends. Why? I believe part of the reason is, well, they know I *know* they're straight. With their straight friends, there's the risk that if they show affection their friends will take it as a romantic overture. It kinda reminds me of my trip to Nepal, where men would hold hands and cuddle with each other without any hint of homosexual desire or homophobia.
Mind you, these are very open-minded guys, but even among their ilk, there seems to be some hesitation to be openly affectionate with each other.
Anyway, I just thought I'd poll people around here to see what they think of these friendships. The friendships between gay men and straight women are already so openly studied that I find it somewhat astonishing that no similar investigation has been done on same-sex friendships.